The present invention relates generally to electric machine components and more particularly to an electric machine stator lamination having a dual phase magnetic material.
With certain electric machine applications the machine's rotor rotates at a high tip speed. In some applications the gap between rotor and stator is filled with a gas or fluid, other than air. As a result, a large amount of mechanical loss may be created from the windage or churning of the fluid and/or gas within the air gap between the rotor and stator.
This churn in the rotor stator gap can be mitigated by providing a smooth surface on the interior core surface of the stator and/or the exterior surface of the rotor. Manufacturing challenges remain with the installation of wedges in the slot closures. The wedges lead to a non-smooth interior stator surface.
The use of slot wedges, depending on the material, may exacerbate slot leakage reactance. The lamination can be made from a continuous piece of material in which the area at the top of the slot is “closed” with magnetic lamination material. While this design provides a smoother stator bore, it leads to increased leakage reactance compared with an “open” slot design. Leakage reactance can limit the high speed power capability of electric machines. Leakage reactance can also lead to a low power factor in the electric machine.
In some electric machines the stator teeth are formed of separate components rather than a continuous, monolithic piece. The stator windings are wound around the separate teeth in a concentrated fashion and then installed into the stator to form a stator core having no slot opening remaining at the top of the slot. This method suffers from manufacturing complexity as it is limited to use with concentrated windings.
Accordingly, there is an ongoing need for improving upon electric machine componentry design, performance, and manufacturability.